


seventy-two hours

by Anonymous



Category: Harry Potter - J. K. Rowling
Genre: Alternate Universe - Canon Divergence, Angst, Blackcest, Child Abuse, Disowning, Emotional/Psychological Abuse, F/F, F/M, Parent/Child Incest, Sibling Incest, Sister/Sister Incest, Sisters, Smut, magical abuse
Language: English
Status: Completed
Published: 2017-08-21
Updated: 2017-12-20
Packaged: 2018-12-18 10:36:31
Rating: Explicit
Warnings: Graphic Depictions Of Violence, Rape/Non-Con, Underage
Chapters: 2
Words: 1,083
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/11872560
Author URL: https://archiveofourown.org/
Summary: Narcissa finds comfort in Bellatrix's bed the night after Andromeda is disowned. Their father finds them. Alternatively: Why Narcissa is such a good Occlumens.





	1. Chapter 1

**Author's Note:**

> I played with the Black sisters' ages a little bit in this fic. Also, the smut is the first chapter; if you want to pretend it's just that, don't read the second chapter. It gets more triggering.

Narcissa and Bellatrix lie tangled together in Bella’s twin bed, Narcissa’s face pressed into Bella’s dark curls.

“I miss her,” she mutters. She wants to Banish any thoughts of the blood-traitor from her mind, but she can’t.

“ _Shhhh,”_ Bella turns over in the bed and her hand wanders up Narcissa’s nightgown, and Narcissa bites her lip, thrusting herself closer to her sister’s hand. Having sex with her sister after Andromeda has been disowned is probably not the best coping mechanism, but it does reassure her that she still has family who loves her. And plus, it isn’t the first time at all.

Bella works a finger into Narcissa, stroking her softly and making her whine. It’s 5AM and nobody else in the mansion is up yet. Their parents managed to sleep fine after disowning their eldest daughter, but Narcissa climbed into Bella’s bed in the middle of the night and clung to her, barely able to sleep.

“You still have me,” Bella says softly, pairing her soft words with fast thrusts into her sister.

“Yeah but —” Narcissa’s protests fail, interrupted by her moans of pleasure as she closes her eyes. She doesn’t particularly care about being quiet — their parents have wards to avoid too much noise entering their room, and she feels that there’s some sort of justice in being so loud with their celebration of sisterhood after Andromeda has been disowned. And frankly? This has been going on for years, Narcissa’s pretty sure her parents know about her and Bella by now. What would two women from the “Toujours Pur” House of Black sharing a bed at their age do other than this, anyway?

“My little sister,” Bellatrix kisses Narcissa’s pale neck, causing Narcissa to make quiet noises of contentment. “All mine,” she whispers before she seals Narcissa’s lips in a passionate kiss, while still having a finger inside of her.

And then the door clicks open.

Bellatrix removes the finger from her sister and jumps up, not even bothering to pull the covers over her naked body. Narcissa just lies there, paralyzed, with her hair and nightgown a mess.

“Get dressed _silently_ and come downstairs,” is all Cygnus Black says, commanding the sisters with an order that he knows will be magically enforced with pain if they don’t follow it fast enough.


	2. The White Room

Narcissa and Bellatrix dress hurriedly, pulling on their robes. When they are both dressed, Bellatrix moves to head out of the door, but Narcissa puts a hand on her older sister’s shoulder, looking up at her with a pleading expression and mouthing “What will happen?”

“Don’t think about it, Cissy. That just makes it worse. And it will be worse for me, anyway,” Bellatrix responds, mouthing back at her. In times like these, and when in solitude at Hogwarts, they’ve perfected the skill of talking without speaking. 

They hurry downstairs, and present themselves in the sitting room of the mansion like the dignified ladies they are. Cygnus storms into the room. He doesn’t say anything, just grabs Bellatrix’s wrist and pulls her up from the chair in a way that Narcissa knows will leave bruises. 

As he pulls Bellatrix away, Narcissa realizes with a sinking feeling in her stomach that she knows exactly what is happening. It’s happened before, but with the betrayal of Andromeda fresh in their father’s mind, Narcissa knows it will be much worse than usual.

Her suspicions are confirmed when there’s the painful snap in her mind that she knows so well, despite it only having happened a handful of times. It feels like a part of her is  _ gone,  _ her magic out of balance and reeling, desperate to feel some presence of Bellatrix’s. But it’s not there. He’s taken Bellatrix to the white room.

***

The worst part of the white room is when she feels her father’s magic and no-one else’s, Bellatrix thinks as she is dragged there. When he hits her downstairs or casts gratuitous curses on her in her room so she can practice her resistance to the Dark Arts, even when he comes into her room late at night and claims her in a way that only Narcissa or her future husband should be able to, she can feel the family magic put up some of a fight and her bond with Narcissa surround her. 

But in the white room, all of that’s gone. 

“You are  _ disgusting,”  _ he says, pushing her up against the mattress - oh no - that is inside the room. “Your sister has betrayed the family by tainting herself with the hands of a Mudblood, and now you have attempted to seduce the only pure child of mine by showing her something that she should only have from her husband. What do you have to say for yourself?”

Bellatrix has done this before, and she knows that apologizing won’t do anything. In times like these, her father thinks she is the devil incarnate, the doom of the Noble and Most Ancient House of Black. She also knows that he is doubtless aware of what she and Narcissa do behind closed doors, but if he wants to make a fuss about it this time, fine. It’ll be over soon, anyway. Probably not tonight, judging by the mattress, but soon. He can’t keep her in this room for too long without breaking both her and his only pure daughter.

“ _ Crucio,”  _ he hisses, and Bellatrix’s body comes alive with pain. She focuses on it, because it’s actual magical sensation, and if she’s not going to be free from this prison until tomorrow she needs as much of that as that as she can. Bellatrix wraps her mind around the magic of the curse, pulling it towards herself and holding it almost like a protective shield so even if she is in worse pain, what happens next feels less mundane and like she is disgusting. 

What happens next is that he Vanishes her clothes and forces her legs apart with a knee, and then lowers himself down to fuck her like she’s some worthless object. 

“Maybe  _ this  _ will teach you what sex is supposed to feel like,” he grunts, coming inside her. Bellatrix maintains a carefully neutral expression, but inside she’s laughing. This is just a pathetic excuse for her father to father to use her like the magic of his marriage bond forbids him from using her mother. Being violated by Cygnus feels like pain and erosion of everything that is natural. Making love to her sister feels like heaven and honey.


End file.
